Airbag module, especiallly a passenger airbag module

ABSTRACT

The invention relates to an airbag module, especially a passenger airbag module, comprising a gas generator arranged in a module housing. The aim of the invention is to create an airbag module which provides the gas bag with a sufficient retaining capacity and enables a load-reducing gas bag deployment which can be variably influenced. According to the invention, the module housing ( 1 ) comprises a continuous gas outlet ( 6 ) on at least one side in the region of a gas bag ( 4 ) to be deployed, and at least one section ( 7 ) extending into the gas bag ( 4 ) is arranged in the region of the gas outlet. Alternatively, the section ( 11 ) can be arranged directly above the gas outlet ( 6   a;    6   b ).

The invention relates to an airbag module, especially a passenger airbagmodule, according to the precharacterizing clause of claim 1.

In order to minimize negative effects on the occupants of a vehicle whenairbags are triggered and in order to ensure a reproduceable functioningof the airbag module, measures are required for the specificallycontrolled deployment of the airbag.

For this, in addition to structural measures on the airbag structuralmeasures on the airbag module are also known. Thus, WO 96/25309discloses an airbag module, in which a chimney-like diffuser extendsinto the airbag. Only one layer of the airbag is situated above thechimney. The diffuser has enlarged discharge openings in the desiredmain direction of deployment. The effect achieved by this is that theairbag has an enlarged surface expansion in this direction.

The disadvantage of this arrangement is that the walls of the diffuserhave to be arranged at a distance from one another in order to permitthe gases to flow through. As a result, the space available for theairbag in the airbag module is limited, which, particularly in the caseof restricted installation conditions, results overall in a high packingdensity.

Japanese laid-open specification 09048318 A discloses an airbagarrangement with a tubular gas generator. A diffuser which has a webextending into the airbag is provided in this airbag arrangement. Thediffuser and the web are manufactured as a sheet-metal part from asingle piece, and extend over the entire length of the tubular gasgenerator, the web running in the center of the diffuser in thedirection of the longitudinal axis of the tubular gas generator. To theside of the web and at a distance therefrom there are a plurality ofdischarge openings in the diffuser, with larger discharge openings beingprovided on one side of the web than on the other side, or there beingdischarge openings only on one side. The airbag is mounted above thediffuser and in both sides of the web. After ignition of the gasgenerator, the airbag is deployed more rapidly on the side with thelarger discharge openings than on the other side. At the same time, thedirection of deployment is also affected as a result.

This arrangement does indeed give the airbag package a relatively largeretaining capacity. However, because of the discharge openings which areprovided at a distance from the web, the path of the gases into theairbag region situated above the web is obstructed. The gases first ofall spread out below the airbag package. This gives rise to the effectthat, at the beginning of the deployment of the airbag, the airbagregions arranged on both sides of the web are suddenly pushed out of themodule housing, which may lead to increased loads on the occupant.

The invention is based on the object of providing an airbag module whichprovides the airbag with a sufficient retaining capacity and permits aload-reducing airbag deployment which can be variably influenced.

This is achieved according to the invention by the features of claim 1or 2.

According to the invention, in the case of an airbag module, especiallya passenger airbag module, having a gas generator which is arranged in amodule housing, the module housing has a continuous gas outlet openingon at least one side in the region of an airbag to be deployed and atleast one web extending into the airbag is arranged in the region of thegas outlet opening. The folded airbag extends primarily to the side ofthe web.

This arrangement has the advantage that the gases are conducted directlyalong the web into the airbag region situated above it because of thearrangement of the web in the region of the gas outlet opening. Apushing-out of the entire airbag package is avoided, and the airbag isdeployed radially outward starting from this region. The outlay onmanufacturing is reduced because of the single opening in the modulehousing. The different arrangement of the web in the region of the gasoutlet opening enables the deployment of the airbag to be influenced indiverse ways. The combination of the features according to the inventiontherefore brings about an improvement both in the outlay onmanufacturing and also in the possibility of influencing the deploymentof the airbag. The retaining capacity for the airbag is onlyinsignificantly limited by the web.

In order to influence the deployment, the web can run directly on theedge of the gas outlet opening. Furthermore, the web may also bearranged above the gas outlet opening. In this case, it may run indifferent directions above the gas outlet opening in accordance with therequired deployment characteristics of the airbag, and may be arrangedat any desired location above the gas outlet opening.

The object is also achieved by an airbag module, especially a passengerairbag module, having a gas generator which is arranged in a modulehousing, in which the module housing has at least one gas outlet openingon at least one side in the region of an airbag to be deployed, and inwhich at least one web extending into the airbag is arranged directlyabove the gas outlet opening. In this case too, the web can run indifferent directions and can be arranged at any desired location.

The web preferably has a smaller length than the space in the modulehousing part for the mounting of the folded airbag, and the web extendsalmost as far as the upper edge of the module housing.

In one preferred embodiment, the module housing is of two-part design,the gas outlet opening and the web being provided on a first part, alsoreferred to as lower part, in which the gas generator is arranged, thefolded airbag being arranged in a second part, also referred to as upperpart, and both parts being connected via flanges between which theblow-in mouth of the airbag is fixed.

When a tubular gas generator is used, the gas outlet opening runs in thedirection of its longitudinal axis. In this embodiment, the web may runboth in the direction of the longitudinal axis of the tubular gasgenerator or transversely to the tubular gas generator or obliquely withrespect to the direction of the longitudinal axis. As a result just ofthis, the deployment of the airbag can be widely influenced. Theposition of the web is selected in such a manner that the packingdensity of the airbag can be set in accordance with the desireddeployment.

In addition, the deployment may be influenced by different crosssections of the web. In one embodiment, the web has a rectangular crosssection. In a further embodiment, the web has a wave-shaped crosssection. In addition to an increased stiffness, the wave shape has theadvantage of facilitating the conducting of the gas flow into the upperfabric layer, since there is a distance between the folded airbag andthe web in the wave troughs and a gas passage thus remains free.

The shape and the profile of the web may also have an influence on thedeployment. Thus, in one embodiment, the web is of bow-shaped design, itbeing possible for this web to be fastened to the module housing onopposite sides of the gas outlet opening or on one side of the gasoutlet opening.

In a further embodiment, the web is angled in such a manner that it atleast partially covers the gas outlet opening. This enables the gas flowto be deflected in a desired direction, and a direct streaming of itagainst the upper fabric layer of the airbag is avoided or reduced.

In a further embodiment, the web has channels for conducting the gasflow. In one embodiment, the channels run rectilinearly, in which casethey run on the outlet side in such a manner that they are directed ontothe airbag layer situated above the web and therefore conduct the gasflow preferably in the direction of this airbag layer. In a furtherembodiment, the channels on the outlet side of the gases run in adifferent direction than the channels on the inlet side, the outlets ofthe channels preferably ending on the end sides of the web.

The invention will be explained in exemplary embodiments with referenceto the drawings, in which:

FIG. 1A shows a cross section through a passenger airbag module;

FIG. 1B shows a longitudinal section through the passenger airbag moduleaccording to FIG. 1;

FIGS. 2A-2F show embodiments with wave-webs;

FIG. 3 shows an embodiment with channels running rectilinearly in theweb;

FIGS. 4A, 4B show an embodiment with angled channels in the web;

FIG. 5 shows an embodiment with a straight web;

FIGS. 6A, 6B show embodiments with bow-shaped webs;

FIG. 6C shows an embodiment with an angled web.

FIGS. 1A and 1B illustrate a two-part module housing 1 which comprises afirst part 1 a, which can also be referred to as lower part, and asecond part 1 b, which can also be referred to as upper part. The lowerpart 1 a of the housing is used for accommodating a tubular gasgenerator 2 and for the separation between a pressure space 3, which isformed in the lower part of the housing, and a folded airbag 4, alsoreferred to as airbag package, which is arranged in the upper part 1 bof the housing. The separating wall region 5 of the lower part 1 a ofthe housing is provided with a continuous gas outlet opening 6 via whichthe gases emerging from the tubular gas generator 2 are conducted intothe airbag 4. A web 7 which projects into a fold of the airbag packageis arranged to the side of the gas outlet opening. Said web runs fromthe separating wall region 5 almost as far as the upper edge of theupper part 1 b of the housing and therefore as far as the upper edge ofthe module housing 1. Only one airbag layer 4 a is situated above theweb 7 while the folded airbag is mounted next to the web 7. The lowerpart 1 a of the housing has an encircling flange 8 and the upper part ofthe housing has an encircling flange 9. The housing parts 1 a and 1 bare connected to each other by means of these flanges. The airbag 4 isalso fixed in the region of its blow-in mouth 10 between these flanges.

The web 7 partially separates the airbag package 4, since it does notextend over the entire length of the upper part 1 b of the housing. Ascan be seen from FIG. 1A, there is a narrower space for the foldedairbag on the left-hand side, next to the web 7, in the direction of thelongitudinal axis of the tubular gas generator 2 than on the right-handside, as a result of which, with at least approximately the same amountof airbag on both sides, a different packaging density can be obtainedand therefore the deployment can be influenced. It can thus be seen inFIG. 1A that the packaging density on the left-hand side is greater thanon the right-hand side. Since the gas outlet opening 6 is also situatedon the right-hand side of the web 7, the airbag is first of all deployedon the right-hand side of the web, the gas flow being conducted by thearrangement of the web 7 in a specific manner into the upper airbaglayer 4 a.

In the following figures, of the module housing 1 only the gas outletopening 6 is illustrated in order to explain the different arrangementthereof with respect to the web and the different shapes of the web.

Thus, FIG. 2A illustrates, on the edge of the gas outlet opening 6, aweb 11 having a wave-shaped cross section. In addition to an increasedstiffness, the wave shape has the advantage of facilitating theconducting of the gas flow into the upper airbag layer (not illustratedin this figure). As can be seen from the plan view of FIG. 2B, there isa distance in the wave troughs 12 between the airbag package 4 and theweb 11, thus enabling gas passages to remain free.

FIG. 2C illustrates an embodiment in plan view, in which the wave-shapedweb 11 is arranged in the center of the gas outlet opening 6. With thisembodiment, a different packaging density on both sides of the web canbe obtained if the gas outlet opening 6 is not arranged centrally, asillustrated in FIG. 1A.

FIG. 2D shows a plan view of the embodiment of FIG. 2A.

FIG. 2E shows a variant in which two gas outlet openings 6 a, 6 b areprovided. The wave-shaped web 11 runs centrally above the latter.

Finally, FIG. 6F illustrates an embodiment in which the wave-shaped web11 is arranged obliquely above the gas outlet opening 6.

FIG. 3 shows an arrangement in plan view, in which a web 13 is providedwith channels 14. The latter run rectilinearly from the gas inlet on thelower side of the web to the gas outlet on the upper side of the web, inthe direction of the upper airbag layer, which is not illustrated inthis figure. The web 13 is arranged centrally above the gas outletopening 6. The channels permit an additional influencing of thedeployment of the airbag.

FIGS. 4 a and 4 b show a web 15 having channels 16. This web is arrangedto the side of the gas outlet opening 6. In this embodiment, thechannels do not run rectilinearly, but rather diverge in the web 15. Atthe gas inlet there are parallel channels 16 a, b which merge in thecenter of the web 15 into channels 16 c, d running obliquely to thelateral end walls 17, 18. These channels also emerge from the web 15 atthe abovementioned end walls. In addition, a connecting channel 16 e isalso formed.

In this embodiment too, the gases emerging from the gas generator areconducted to the upper airbag layer. The oblique orientation of the gasflow constitutes an additional possibility for influencing thedeployment of the airbag.

In FIG. 5, a web 19 is arranged directly on the edge of the gas outletopening 6 parallel to the longitudinal axis 20 of a tubular gasgenerator (not illustrated). In this embodiment, the web 19 is shorterthan the gas outlet opening. The web is fastened to the module housing1, only part of which is illustrated in this figure.

FIG. 5 shows just one possibility for arranging the web. The packingdensity and therefore the desired deployment characteristics can be setby means of different lengths and other positions of the web withrespect to the gas outlet opening.

FIGS. 6A-C illustrate further, alternative embodiments of webs as anaddition to FIGS. 2 and 3. FIG. 6A shows a bow-shaped web 23 whichextends in the direction of the longitudinal axis 20 of the gasgenerator (not illustrated). This web spans the gas outlet opening 6 inthe center thereof and is fastened at its opposite edges to the modulehousing 1.

In the case of the exemplary embodiment of FIG. 6B, a bow-shaped web 24is provided, which web likewise extends in the direction of thelongitudinal axis 20 of the gas generator, that is fastened to themodule housing 1 only on one side of the gas outlet opening 6 andextends only approximately as far as the center of the gas outletopening 6.

In the embodiment of FIG. 6C a web 25 which is angled in the upperregion is provided. The angled section 25 a partially covers the gasoutlet opening 6 in FIG. 6C. However, this section may also bedimensioned in such a manner that it completely covers the gas outletopening. The partial or complete covering enables the gas flow to bedeflected in a desired direction and reduces or avoids a directstreaming of it against the upper airbag layer.

The invention is not restricted to the embodiments illustrated in thefigures. Thus, the webs may have other shapes and may be arranged atother locations. Furthermore, a plurality of webs may also be provided.

1-22. (canceled)
 23. A passenger airbag module comprising: a gasgenerator arranged in a module housing; wherein the module housingincludes a space containing a folded airbag and includes a gas outletopening on a side of the housing adjacent the airbag; wherein thehousing includes a web located on a side of the gas outlet opening,wherein the web extends into the folded airbag.
 24. The airbag module ofclaim 23, wherein the web extending into the airbag is arranged directlyabove the gas outlet opening.
 25. The airbag module of claim 23, whereinthe length of the web along the side of the gas outlet opening isshorter than the space in the module housing for the folded airbag, andwherein the web extends away from the opening to a position adjacent anupper edge of the module housing.
 26. The airbag module of claim 23,wherein the airbag is folded so that there is only one airbag layerabove the web.
 27. The airbag module of claim 25, wherein the modulehousing includes two-parts, the gas outlet opening and the web beingprovided on a first part, in which the gas generator is arranged, thefolded airbag being arranged in a second part, and both parts beingconnected via flanges between which a blow-in mouth of the airbag isfixed.
 28. The airbag module of claim 23, wherein the gas generator istubular and the gas outlet opening runs in the direction of thelongitudinal axis of the gas generator.
 29. The airbag module of claim28, wherein the web extends in the direction of the longitudinal axis ofthe tubular gas generator.
 30. The airbag module of claim 28, whereinthe web extends transversely to the longitudinal axis of the tubular gasgenerator.
 31. The airbag module of claim 28, wherein the web extendsobliquely to the direction of the longitudinal axis of the tubular gasgenerator.
 32. The airbag module of 23, wherein the web extends directlyalong the edge of the gas outlet opening.
 33. The airbag module of claim25, wherein the web is arranged above the gas outlet opening.
 34. Theairbag module of claim 23, wherein the web has a rectangular crosssection.
 35. The airbag module of claim 23, wherein the web has awave-shaped cross section.
 36. The airbag module of claim 23, whereinthe web is bow-shaped.
 37. The airbag module of claim 36, wherein thebow-shaped web is fastened to the module housing on opposite sides ofthe gas outlet opening.
 38. The airbag module of claim 36, wherein thebow-shaped web is fastened to the module housing on one side of the gasoutlet opening.
 39. The airbag module of claim 23, wherein the web isangled so that the web at least partially covers the gas outlet opening.40. The airbag module of claim 23, wherein the web has a plurality ofchannels having a plurality of outlets for conducting the flow of gasfrom the gas generator into the airbag.
 41. The airbag module of claim40, wherein the channels extend rectilinearly.
 42. The airbag module ofclaim 40, wherein the outlets of the channels are positioned so that thegas flow is directed onto the airbag layer situated above the web. 43.The airbag module of claim 40, wherein the outlets of the channelsextend in a different direction than the inlets of the channels.
 44. Theairbag module as claimed in claim 40, wherein the outlets of thechannels are positioned to terminate on a plurality of sides of web.